1. Field of the Invention
This invention relates to inflatable devices and, more particularly, inflatable devices consisting of an inflatable member mounted to a rigid but self-coiling sheet.
2. Prior Art
Inflatable devices are popular because they are light, inexpensive, and they provide a cushioned support for the user. An additional advantage inherent in most inflatable devices is that the device becomes relatively compact and easy to store upon deflation. The inflatable portions of these devices usually consist of a plurality of tubes made of a relatively thin-walled flexible material, such as plastic or a polyester fabric coated with a plastic, joined together to form one or more chambers. A valve is fitted to a wall of one of the tubes and the entire inflatable portion may be inflated from this one valve. It is desirable to have an inflatable portion having relatively thin walls made of a flexible material because this reduces the overall weight of the device and provides an inflatable portion that is relatively easy to inflate. In some instances, the inflatable portion can be inflated by the lung power of the user of the device.
However, an inherent disadvantage in providing an inflatable portion having thin walls is that the walls are then subject to failure as a result of contact with the environment of the inflatable device. This is particularly true when the inflatable portion forms a part of a vehicle such as a toboggan or inflatable boat which moves and has a frictional engagement with relatively unyielding elements in its surroundings. Therefore, it is desirable to interpose a relatively rigid sheet between the inflatable portion and the environment to reduce the frictional contact of the inflatable portion and thereby reduce the likelihood of a puncture or failure by abrasion.
For example, U.S. Pat. No. 3,319,972 is directed to a collapsible sled having a head section composed of a stiff or rigid material and a flexible sheet extending rearward of the head section upon which an inflatable load supporting section is mounted. When the load supporting section is inflated, passengers on the toboggan are provided with a cushioned seat which absorbs shocks encountered while the toboggan is travelling. Upon deflation, the inflatable load supporting section and the flexible sheet upon which it is mounted may be rolled into a coil and placed inside the concavity of the rigid head section. A disadvantage inherent in this device is that the user must manually roll the load supporting section and flexible sheet into the desired coil.
Another example of an inflatable vehicle is disclosed in U.S. Pat. No. 3,432,182. This patent discloses an inflatable toboggan having a plurality of inflatable tubes interconnected to form a single chamber and joined at their peripheries by a rope or cable which serves as a handhold. However, this device lacks a rigid bottom sheet which would prevent the inflatable tubes from becoming worn or punctured by obstacles on the terrain along which the vehicle travels. Again, this device must be coiled manually for storage when deflated, a time-consuming procedure.
U.S. Pat. Nos. 3,199,888 and 3,140,878 are directed to toboggans having flexible bottom sheets but no inflatable members. Each of these patents discloses a device that can be coiled for storage by rolling the body of the toboggan about an axis which is normal to the longitudinal dimension of the toboggan. Although coilable for storage, these devices lack the cushioning benefits of an inflatable member. Also, each of these devices must be coiled by hand for storage.
Accordingly, there is a need for an inflatable device in which an inflatable member is mounted to a relatively rigid supporting sheet and which eliminates the need of being manually coiled upon deflation of the inflatable member.